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<a href="mailto:docerrors@microchip.com&subject=MPLAB Harmony Documentation Feedback (Topic ID: DRV_I2C_ReadTransferAdd@DRV_HANDLE@uint16_t@void * const@size_t@DRV_I2C_TRANSFER_HANDLE * const Topic Title: DRV_I2C_ReadTransferAdd Function)&body=Thank you for your feedback! Please include a description of your feedback, and indicate whether you are reporting an an error in the documentation or an enhancement.">Documentation Feedback</a><br> <a href="http://support.microchip.com" target="_blank">Microchip Support</a></div>
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DRV_I2C_ReadTransferAdd Function</div>
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This function schedules a non-blocking read operation. The function returns with a valid transfer handle in the transferHandle argument if the read request was scheduled successfully. The function adds the request to the driver instance transfer queue and returns immediately. While the request is in the queue, the application buffer is owned by the driver and should not be modified. The function returns <a href="00276.html" target="topic">DRV_I2C_TRANSFER_HANDLE_INVALID</a> in the transferHandle argument:</p>
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<li class="Element600">if a buffer could not be allocated to the request</li>
<li class="Element600">if the input buffer pointer is NULL</li>
<li class="Element600">if the buffer size is 0</li>
<li class="Element600">if the driver handle is invalid</li>
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&nbsp;</p>
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If the requesting client registered an event callback with the driver, the driver will issue a DRV_I2C_TRANSFER_EVENT_COMPLETE event if the buffer was processed successfully of DRV_I2C_TRANSFER_EVENT_ERROR event if the buffer was not processed successfully.</p></div>
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C</div>
<div class="Element101"><div class="Element100"><pre class="Element100"><strong><span style="color: #000080">void</span></strong> <strong><span style="color: #000000">DRV_I2C_ReadTransferAdd</span></strong>(
    <strong><span style="color: #000080">const</span></strong> <a href="00257.html" target="topic">DRV_HANDLE</a> <strong><span style="color: #000000">handle</span></strong>, 
    <strong><span style="color: #000080">const</span></strong> uint16_t <strong><span style="color: #000000">address</span></strong>, 
    <strong><span style="color: #000080">void</span></strong> * <strong><span style="color: #000080">const</span></strong> <strong><span style="color: #000000">buffer</span></strong>, 
    <strong><span style="color: #000080">const</span></strong> size_t <strong><span style="color: #000000">size</span></strong>, 
    <a href="00275.html" target="topic">DRV_I2C_TRANSFER_HANDLE</a> * <strong><span style="color: #000080">const</span></strong> <strong><span style="color: #000000">transferHandle</span></strong>
);</pre></div></div>
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Preconditions</div>
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<a href="00264.html" target="topic">DRV_I2C_Open</a> must have been called to obtain a valid opened device handle.</p></div>
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Parameters</div>
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Parameters&nbsp;</div></td><td class="Element304" valign="top" width="65%">
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Description&nbsp;</div></td></tr><tr>
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handle&nbsp;</div></td><td class="Element306" valign="top" width="65%">
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A valid open-instance handle, returned from the driver's open routine <a href="00264.html" target="topic">DRV_I2C_Open</a> function.<br>&nbsp;</div></td></tr><tr>
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address&nbsp;</div></td><td class="Element306" valign="top" width="65%">
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Slave address<br>&nbsp;</div></td></tr><tr>
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buffer&nbsp;</div></td><td class="Element306" valign="top" width="65%">
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buffer where the read data will be stored.<br>&nbsp;</div></td></tr><tr>
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size&nbsp;</div></td><td class="Element306" valign="top" width="65%">
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Transfer size in bytes.<br>&nbsp;</div></td></tr><tr>
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transferHandle&nbsp;</div></td><td class="Element306" valign="top" width="65%">
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Pointer to an argument that will contain the return transfer handle. This is <a href="00276.html" target="topic">DRV_I2C_TRANSFER_HANDLE_INVALID</a> if the request was not successful.&nbsp;</div></td></tr></table></div></div>
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Returns</div>
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None</p></div>
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Remarks</div>
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This function is thread safe in a RTOS application. It can be called from within the I2C Driver Transfer Event Handler that is registered by the client. It should not be called in the event handler associated with another I2C driver instance. It should not be called directly in an ISR. This function is available only in the asynchronous mode.</p></div>
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Example</div>
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<div class="Element13"><div class="Element12"><pre class="Element12">uint8_t myBuffer[MY_BUFFER_SIZE];
<a href="00275.html" target="topic">DRV_I2C_TRANSFER_HANDLE</a> transferHandle;

<i><span style="color: #008000">// myI2CHandle is the handle returned</span></i>
<i><span style="color: #008000">// by the DRV_I2C_Open function.</span></i>

<i><span style="color: #008000">// slaveAddress is address of I2C slave device</span></i>
<i><span style="color: #008000">// to which data is to be written</span></i>

DRV_I2C_ReadTransferAdd(myI2CHandle, slaveAddress, myBuffer, MY_BUFFER_SIZE, &amp;transferHandle);

<strong><span style="color: #000080">if</span></strong>(transferHandle == <a href="00276.html" target="topic">DRV_I2C_TRANSFER_HANDLE_INVALID</a>)
{
    <i><span style="color: #008000">// Error handling here</span></i>
}

<i><span style="color: #008000">// Event is received when the buffer is processed.</span></i></pre></div></div>
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<a href="mailto:docerrors@microchip.com&subject=MPLAB Harmony Documentation Feedback (Topic ID: DRV_I2C_ReadTransferAdd@DRV_HANDLE@uint16_t@void * const@size_t@DRV_I2C_TRANSFER_HANDLE * const Topic Title: DRV_I2C_ReadTransferAdd Function)&body=Thank you for your feedback! Please include a description of your feedback, and indicate whether you are reporting an an error in the documentation or an enhancement.">Documentation Feedback</a><br> <a href="http://support.microchip.com" target="_blank">Microchip Support</a></div>
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